Editing Uuencoding (section)

{{Short description|Form of binary-to-text encoding}}
{{distinguish|text=[[Percent-encoding|URL encoding]]}}

'''uuencoding''' is a form of [[binary-to-text encoding]] that originated in the [[Unix]] programs '''uuencode''' and '''uudecode''' written by [[Mary Ann Horton]] at the [[University of California, Berkeley]] in 1980,<ref>{{Cite web |last=Horton |first=Mark |title=UUENCODE(1C) UNIX Programmer's Manual |url=https://www.tuhs.org/cgi-bin/utree.pl?file=4BSD/usr/man/cat1/uuencode.1c |access-date=2020-11-10 |website=The Unix Heritage Society |language=en-US}}</ref> for [[code|encoding]] [[Binary numeral system|binary]] data for transmission in [[email]] systems.

The name "uuencoding" is derived from [[Unix-to-Unix Copy]], i.e. "Unix-to-Unix encoding" is a safe encoding for the transfer of arbitrary files from one Unix system to another Unix system but without guarantee that the intervening links would all be Unix systems. Since an email message might be forwarded through or to computers with different [[character set]]s or through transports which are not [[8-bit clean]], or handled by programs that are not 8-bit clean, forwarding a binary file via email might cause it to be corrupted. By encoding such data into a character subset common to most character sets, the encoded form of such data files was unlikely to be "translated" or corrupted, and would thus arrive intact and unchanged at the destination. The program '''uudecode''' reverses the effect of '''uuencode''', recreating the original binary file exactly. uuencode/decode became popular for sending binary (and especially compressed) files by email and posting to [[Usenet]] newsgroups, etc.

It has now been largely replaced by [[MIME]] and [[yEnc]]. With MIME, files that might have been uuencoded are instead transferred with [[Base64]] encoding.